Preheat oven to 170°C. Butter and line 2 x 6" round cake tins.
Place sugar into the Thermomix bowl and mill 10 sec/speed 10. Add butter and chop 20 sec/speed 5 or until combined. Insert butterfly and whip 2 min/Butterfly/speed 3.
Add eggs one at a time while mixing 20 sec/Butterfly/speed 3.
Add yoghurt, vanilla, cornflour, baking powder, baking soda and salt and mix 10 sec/Butterfly/speed 3.
Add half the flour and mix 5 sec/Butterfly/speed 3. Add the milk and mix 5 sec/Butterfly/speed 3.
Add the remaining flour and mix 5 sec/Butterfly/speed 3. Add the Raspberry Coulis (and food colouring, if using) and mix 5 sec/Butterfly/speed 3.
Take Butterfly out and use a scraper to bring the batter together completely.
Pour equally between 2 cake tins. Bake for 50 minutes - 1 hour. Or when a skewer inserted into the centre comes out clean.
Cool in the tin for 15 minutes, then place cakes on to a cooling rack to cool completely before icing.
When cake is completely cool, using a serated knife, level the top and bottom of the cake. This will give perfect pink layers (no brown crumb line) and cut each cake in half so you have 4 layers.
Using the Ermine Frosting, ice cake with a piping bag or using a spatula/knife. For a smooth edge do a crumb coat, then refrigerate for at least 30 minutes before doing a final coat of icing. Decorate top with pearls or pink baubles of choice. Candles optional, but so cute!